Pressure regulating device for fluid supply systems



April 28, 1942. P, w. THORNHILL. ET AL 2,280,937

PRESSURE REGULATING DEVICE FOR FLUID SUPPLY SYSTEMS Filed April 25, 1941/ZQ/ w. W

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Patented Apr. 28, 1942 UNITED STATES PATE PRESSURE REGULATDJG DEVICE Foa4 v FLUID SUPPLY sYsrEMs Peter Warborn Thornhill and John Keith Simpfson, Leamington Spa, England, assignors vto p Automotive ProductsvCompany Limited, Leamf ington Spa, Warwickshire, England ApplicationApril 25, 1941,` SerialNo.' 390,418 In Great Britain February 26, 19403` Claims. i

value, the iluid pressure at that side of 'the non-i return valve remotefrom the pump being arranged to hold the blow-oil valve open until apredetermined reduction has occurred in the iluid pressure of theaccumulator or equivalent.`

In' particular it is the object oi.' the invention to provide a compactand lefllcient form'oi Dres-` sure regulating device in which theoperation of the blow-ofi valve is decisive andy in which the`difference between the accumulator or equivalent pressure. serving toopen the blow-off valve, yand the pressure at which the blow-oi!` valverecloses. may be made relatively small.

. In a pressure regulating device of the kind above referred to,accordingxto the invention theiorce exerted 'by the pressure fluid andtending to urge the blow-oli valve towards its open position, iscounteracted byfa spring device which is arranged so that the closingi'orce'it exerts I upon the blow-oil valve when the latter isin itsiully closed position, is substantially greaterthan the force which saidspring device applies to the blow-oil valve when the latter is open.'I'he use oi a spring device having this action enables the blow-01Tvalve to open in a decisive manner so as to avoid wire-drawing oftheduid, the whole device being light and compact and being particularlysuitable for inclusion in the liquid pressure remote control systemswhich now commonly form part of air and` other craft.

Therel is further provided according tothe invention a. pressureregulating device oi the kind referred to, wherein the vblow-olf valveisf balanced with respect to the pressure fluid disposed between thepump and the non-retum valve, or else tends to beurgcd open by saidpressure uid, said `blow-oil valve being closed .by a spring devicewhich is arranged so that theforceit exerts upon the blow-ofi valve whenthe latter is in its closed positiony is substantiallyA greater than theforce which said spring device blow-oil.' valve when the 'latter appliesto' the is open. l

As a."4 feature of the invention. in a pressure regulating device of thekind referred to a plu'- (crisi-,153) V Y j l i n rality of springsarecaused lnormally to act on the blow-off valve to hold it closedagainst theA pump pressure, but the latter, upon increasing suillcientlyto open th'e blow-oil valv'el and pass therethrough,A actsV upon apiston or equivalent member which removes the force of at least one 1 ofsaid springs from the blow-oil' valve so as to enable said valve to openeasily tov its full extent under' the influence of the pressureiluid l0in the accumulator or equivalent.4 l

kind above referred to, according to theinvention a spring device, whichservesv to hold the blow-olfV valve closed against `the fluid pressureso that the force which it exertsfupona valve member of the blow-oil`valve decreases as' said member moves to itsopen pasition.y

Preferably the blow-oli valve comprises an axially slidable valve memberwhich is urged closed by a main spring 'acting directly on said valvemember, and by an auxiliary spring acting upon a piston member, `whichlatter is slid-A ably mounted relative to the valve Vmember and isarrangedto be acted upon by pressureiiuid when the valve member opens,sothat said'piston member compresses the auxiliary spring and removesthe force thereof from the blow-olf valve member. The blow-ofi valvemember may have, intermediate its length, a radial ilange which isarranged toclose. an annular seating of the blow-oifvalve, and which isurged towards said seating by the piston member, under the action of theauxiliary spring.` I f desired the is common to theblow-oif valve, saidvalve mem; ber conveniently engaging at `its end with an annular seatingformed upon `a sleeve, which latter is axially slidable in a'iiuid-tightmanner within a passage leading from the pump tothe accumulatorI orequivalentfso that when the seating is engaged, the said passageis'complete- 1y closed. Thus thejfluid pressure in theaccumulator orequivalent mayact upon the sleeve is lpreferably slightly smaller than`theoutside diameteroi the sleeve, sol that the pressure of thevalvemember, can Ieasily shift the latter to its openpo'sition when oncethe opening move# Further, in a pressure regulating device of the l inthe accumulator or equivalent,-is `arranged non-return valve may have a-valve member which and the end'of the valvemember conjointly, to holdthe valve `member yagainst the action of l the main spring, when` theblow-dif valve is open. The diameter of the ilange .on the valve memberingupon the sleeve and the adjacent end `oil ment has been started bythe pump delivery pressure acting on the area of the ilange.

In another arrangement a variable leverage device is operativelyinterposed between the blow-off valve and the spring serving to loadsaid valve, said variable leverage device conveniently comprising asubstantially triangular member which is pivoted at one angle to thebody of the pressure regulating device, and has its other two angles inengagement, respectively, with the spring device, and with a memberacted upon by the uid pressure in the accumulator or equivalent, thearrangement being such that as the stress in the spring device isincreased, the lever# age aorded bythe triangular member is alsoincreased, but to a greater extent, so that the ,force applied by thespring device to the valve member is actually reduced. If desired a pairof substantially triangular'members may be arranged in overlappingrelationship, said members being pivoted to the body at diametricallyopposite positions. Further, the blow-olf valve may -comprise a plungerarranged to slide axially within a bore, under the action of thepressure iluid in the accumulators or equivalent, and having-agroove orother recess, whichlatter is in permanent'connection with the pumpdelivright', as seen in Figure 1. The plug 29 has a screw-threadedspigot 34 adapted for connection to the pipe I1 and a passageway 35through this spigot leads to the inside of the sleeve 3|. The

bore 30 in the plug 29 is placed in communication with the pipe II bymeans of a series of radial holes 36, an annular groove 31 and aconnection boss 38. The plug 29, which has a packing ring 39 topreventlleakage of liquid, bears Figure 2 is a similar view but showinga modi- ;fied construction of'pressure regulating device;

Figure4 3 is a fragmentary sectional elevation taken on the line 3-3 ofFigure .2; and

Figure 4. is a fragmentary sectional elevation of the variable leveragedevice included in Figure 2, the parts being in the positions which theyoccupy when the blow-olf valve is open.

The pressure regulating valve device is indiu cated generally at I inFigure 1, and is connected by a pipe Il with the delivery'connection I2of a continuously driven pump I3, the inlet connection I4 of whichlatter is connected with a return pipe I5 and with a reservoir I5 forspare working liquid. A pressure outlet pipe I1 leads fromvthe device I0to a hydraulic accumulator I3, while the outlet from the latter isconnected by 9, pipe I9 with a selector valve device 20. From this apair of interchangeable ow and return pipe lines 2| and'22 lead to adouble-acting slave cylinder-unit 23, the piston 24 of which is adaptedto be moved positively ineither direction, depending upon the settingofthe selector valve 2|).l The return 'pipe I5, ofcourse, leads from theselector valve 20 and is connected at 25 with the pressure regulatingdevice- I0.

The pressure regulatingdevice comprises a body 2s which reformed with alongitudinal bore 21, the latter being screw-threaded at one end for`the reception of a spring housing 23 and at its other end for a plugmember 29. 'I'he latter is itself formed with an axial bore 30, withinwhich a sleeve 3| ls slidably mounted, said sleeve being provided with apacking ring 32 upon its outside for the purpose of preventing leakingof liquid. The sleeve 3|. isrecessed for the accom'- modation of `alight coiled compression spring 33 vserving to urge said sleeve 3|.`towards the 75 at its end against an annular seating member 40 and holdsthe latter securely in position against a shoulder 4| in the bore 21.

The seating member 40 has its surface 42 bounding a central aperture ofcountersunkA shape so as toact as a seating for the adjacent relativelysharp edge of a radial flange 43 formed on the stem 44 of a valvemember, which latter `is indicated generally at 45.- Ait its left-handend the stem 44 is formed with a conical head 45 adapted to engage theedge of the internal curved surface of the sleeve 3| andY thuscompletely close the passageway through said sleeve. .The opposite endof the stem 44 is fitted with a substantially cylindrical block 41,which is arranged to slide through a rubber or other resilientpackingwasher 48, the latter being lsupported between a pair of metal washers49 and 50 which have appreciable clearance relative to the block 41 soas to permit the valve member to move into accurate alignment witheither the sleeve 3| or the seating member 40, depend-lk ing uponIwhether the blow-01T valve 40, 43'isy open or closed.

The washers 49 and 50 are held in position by an auxiliary coiledcompression spring 5|, which, at its other end, bears against a pistonmember 52. 'I'his member is adapted to engage with the radial flange 43of the valve member 45 and its periphery' is a smooth sliding fit withinthe bore 21. No packing means are provided, however, as it is desiredthat a slight leakage of liquid past the piston member 52 should bepermitted.

The cylindrical block 41 of the Valve member 45 is urged towards theleft by a main spring 53 acting through a plate 54, the force exerted by43, co-operatingr with the seating member 49,

serves as the blow-off valve, which, when open, permits the deliveryfrom the pump |3-to ow freely back to the inlet I4 by way of the returnpipe I5. It will be seen that the flange 43 is normally held rmlyagainst the seating member 40 by the main spring 53 acting through thevalve stem 44, and at the same time by the auxiliary spring 5I actingupon the piston member 52. As a result the liquid delivered underpressure by the pump |3 through the pipe II acts upon the end surface 58of the sleeve 3|, and by urging the latter to the left -against thespring yis vable to flow through the pipe |1 and into the accumulatorI8. As the vaccumulator becomes charged, the pressure of the liquid inthe pipe II and in the annular space 59 increases until Y said liquid,acting simultaneously upon the lefthand surface of the flange 43 andupon the conicalsurface of the head able yto overcome the combined forceof the main spring 53 and y secured by a variable leverage'device.

against the force exerted by the auxiliary springYV I, and owing to theconsequent separation of the piston member 52 and the ange 43 a drop inpressure occurs in the annular space 59, so that the sleeve 3| movesback into engagement with the head 46. The pressure liquid in the pipeI1 is thus able to act upon the valve member 45 over an areacorresponding to that of the bore 36, the force so produced tending tomove the valve member 45 towards the right. 'Ihis force is, moreover,only resisted by the main spring 53, for the liquid pressure acting uponthe piston member 52 is quite 'suiiicient to hold pump I3 passes throughthe pipe Ila, the nonthe auxiliary spring 5I in a compressed state. It

follows therefore that the valve member 45 is moved decisively to itsfully opened position, and it will be noted that in this state the forceexerted by the spring 53 tending to close the valve is substantiallyless than the force produced by the springs 53 and 5|, which act incombination upon the valve member `45 when the latter is in its closedposition. As the pressure in the `accumulator |8 drops, there comes atime when the force upon the sleeve 3| and head 46 is unable to resistthe spring 53, and the valve member 45 therefore moves to the left andassumes its closed position. The liquid within the space 66 is able to,escape through apertures 8| in the piston member 52, so that the partsresume the positions shown in Figure 1 and the liquid delivered by thepump I3 has its pressure built up and is utilised for recharging theaccumulator I8.

In the `modified form of device shown in Figures 2 to 4 the reduction inthe eil'ective force of the main spring as the blow-off valve opens is lThe pressure regulating device is again indicated at I6 and the parts ofthe remote controlsystem are the same as before, except that anon-return valve unit 6I is provided separately from the device I6 andis connected between the pipes II and I1 by means of pipes IIa and I1arespectively. 'I'he plug 29 is again provided with a bore 36, whichcommunicates with the pipe II by way of radial holes 36 and an annulargroove 31. The bore 36 contains an axially slidable piston valve member62, which is a substantially liquidtight fit within the bore 36 and isformed with a waist portion 63, the annular space 64 surrounding whichis in permanent communication with the holes 36. The piston valve member62 is adapted to slide to the right, and when the waist portion 63extends beyond the edge 65 of the plug member 29, as shown in Figure 4,free communication is established between the pipe II and the returnpipe I5. e

The piston valve member 62 is normally urged towards its left-handposition against a stop cap 66 by means of a main spring 53 containedwithin a spring housing 28. The latter has an adjustableplug 61 againstWhichthe outer end of the spring 53 butts, a lock nut 68 being providedto preserve the -axial adjustment of the plug 61. The inner end of themain spring 53 latter slides within a bore 1I formed in the plug 61 andis engaged by a substantially cylindrical thrust member 12 through themedium of a ball 13. The spring housing 28 is formed at its inner endwith a diametral groove 14, which accommodates a pair ofsubstantiallytriangular lever members 'indicated at 15 and 16respectively, said members being vpivoted at diametrically oppositepositions by means of transverse pins 11 and 1.6

respectively. It will be noticed that in each case the pivot pin isdisposed adjacent one angle of the corresponding triangular levermember, while the other angles engage respectively with the Apistonvalve member 62 and with the thrust mem- "ber 12, the lever members ,15and 16 being cut away, aswill be' seen in Figure 3, so as to enable themto be arranged in overlapping relationship. i

With the parts in the positions shown in Figure 2, the blow-off valveconstituted by the piston valve member 62 and the plug 29 is closed andconsequently the pressure liquid delivered by the return valve device6|, and pipes I 1a and I1 to the hydraulic accumulator I8. This pressurei liquid, by passing through a connection 1,9, gains access to a space86 bounded by the end surface of the piston valve member 62, so that thepressure of said liquid acts to force the piston valve member 62 towardsthe right( The main spring 53 is so adjusted by means of the plug member61 that when an appropriate pressure is reached in the hydraulicaccumulator I8, the force on the y in the case of the lever member 15,the point of contact between said member 'andthe piston valve member 62progressively rises, whereas the point of contact between the levermember 15 l chanical advantage afforded by the lever memengages a flange69 upon a plunger 16, which 75 bers 15 and 16 is arranged to increase ata substantially greater rate than the force exerted byv the main springv53 increases, so that when the piston valve member 62 commences to openunder the action of the force exerted by the liquid in the space 86,said opening movement is counteracted by progressively decreasingiresistance, with the result that the valve opens decisively and,moreover, remains fully open until the pressure in the space 86 hasdropped to such a value that the spring 53 is able to overcome it. Thevariable leverage device constituted by the lever members 15 and 16 can,of course, be readily designed to g'ive any desired difference betweenthe pressure at which the piston valve member 62 is closed and that atwhich it subsequently opens.

Besides beingapplicable in conjunction with vention is especially usefulin cases where a slave unit is'fed with pressure liquid directly from acontinuously running Dump, for when the piston reaches the end. of itsstroke the consequent pressure rise in the liquid supplied by the pumpcan be utilised to operate the valve member (such as t5 or t2) so as toplace the pump delivery in communication with the pump inlet, at thesame time maintaining the pressure in the slave unit.

The invention may of course be applied to other constructions ofpressure regulating device apart from those given by way of example.

What we claim is:

1. A device for the regulation of fluid pressure in a reservoir suppliedthereto by a pump, compressor or the like comprising an axially movablevalve adapted to open under the influence of a predetermined pressure,resilient means urging said valve to its closed position, a pistonmember slidably mounted relative to and normally abutting said valve andarranged to be acted upon by its length, an annular detachable memberhaving an inclined seating surface cooperating with said iiange,resilient means urging said ange against said seat, means normallyabutting said flange and slidably mounted relative to the valve memberand arranged to be acted upon by pressure iiuid when the iiange opens,and a second resilient means acting through the abutting means to urgethe ange to closed position so constructed and arranged that saidabutting means will, under the influence of pressure, compress thesecond resilient means and remove allv force thereof from the flangeonce the latter has opened.

3. A device for the regulation of fluid pressure supplied to a reservoirby a pump, compressor or the like comprising means having a sleeveform-` ing a valve seat, an axially slidable valve member having a iradial ange intermediate its length, a sealing head formed on one end ofsaid member and cooperating with said valve seat, an annular seatcooperating with said flange, re silient means urging said flangeagainst said annular seat, a piston normally abutting said ange andmovably mounted relative to said member and arranged to be acted upon byuid pressure when the flange is unseated, and a second resilient meansurging said piston and said ange to closed positions, so constructed andarranged that said piston will, under the influence of pressure,compress the second resilient means and remove all force thereof fromthe flange once the latter has opened.

PETER WARBORN THORNHILL. JOHN` KEITH SIMPSON.

